Improvement in machines for making wood-screws



BSheets-Sheetl. C. D ROGERS.

MACHINES FOR MAKING WOOD SCREWS. No.177,Z83. atented May 9,1876.

Wmusssss. Y INVENTOR.

N-PUERS. PHOTO-LITNOQRAPHER. WA3HINGTCIN. D C.

5 Sheet.s-Sheet 2.

C. D. ROGERS.

MACHINES FOR MAKING WOOD SCREWS. No.1'77,Z83. Patented May 9., 1876.

wl ws sfl -h INVENTOR M i N.PETERS, PHOTO LITNOGRAPHK WASHING'ION. D. Q

5 Sheets-Sheet 3.

C. D. ROGERS. MACHINES FOR MAKING WOOD SCREWS.

No.177,Z83. Patented May 9,1876.

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N-FETERS, I'HUWLITQOGRAPHER. WASNINGTQ). D. C.

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, C. D. ROGERS. MACHINES FOR MAKING woonscmvvsq No.177,Z83. Patented May9,1876.-

WITNESSES. INVENTOR.

I N-PETERS. PNOTQ-LITWAPIER. WASHINGTON. D C.

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c D. mamas. MACHINES FOR MAKING WOOD SCREWS.

No. 177,283. Patented Ma a, 1876.

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N. PEIERS, PHOTO-UTHOGRAPHER. WASHINGTON. 0 CV threads.

'brought-to an-edge by cutting to a sufficient to the-same edge. Thelength ofthis imperfect CHARLES D. ROGERS, OF PROVIDENCE, RHODE ISLAND.

lM PROVE M-E'NT IN M ACHINES FOR MAKING woon-sclaews.

Specification forming part of Letters Patent No. 177,283, dated May 9,1876; application filed March;27, 1876.

To all whom it may concern Be it known that I, CHA LES D. ROGERS, ofProvidence, in the; State of RhodeIsland, haveinvented an Improvement inthe Manufacture of Wood-Screws, of which the follow-. ing is aspecification:

The invention relates to the manufacture of i that classof wood-screwsin which the threads areformed; by cutting away the metal between themby atool or chaser having a form corresponding to the space left betweenthe.

Heretofore, in the manufacture of woodscrews, when the portionimmediately below the neck, which is the part usually termed the cone ofthe screw, has been threaded by the same tool which has been used tothread the remainder of the-body of the screw, the thread over, thecone, instead of being brought to an edge, has been. left with a flattop,this flat top gradually decreasing in width until, at thetermination of the cone, it came to an edge, which was continued for therest of the screw.

It isobvious that, in cuttinga screw of any givenlead by a chaser havingitssides inclined tothe axis of the screw, the thread can 'be depth;and-it is also obvious that a screw cannot. be cut from a cylindricalwire so as to leave a conical body beneath the thread, and at the sametime carry the tool everywhere to a uniform depth. Consequently, with aconical body, the thread has a thick edge, and the shallower the cut'thethicker the, edge. This. has caused the old screw to be imperfect, forthe wide or thick part of the thread %1 over the cone does not followthe part brought 3 toan edge-over the cylindrical portionof the body asreadily as ifall'the parts were brought part of the threadis generallyreduced as much as possible by quickly bringing the cut to its maximumdepth; but whilethisdoesnot wholly remove the evil it introduces anotherwhich it is desirable to avoid. The screw is most apt to breakimmediately below the neck, or at the part where in cutting the threadits body is reduced from the full diameter of the blank to the-diameterat the bottom of thecut, and-the more sudden thisreduction the greateris-the liability of the screw to be broken.

Attempts have been made to bring the difficulty above stated; and itconsists in Esame. 5 are sectional elevations taken on the dotted blankand presenting it to the chaser.

cost of manufacture, but involves a different inclination of the sidesof the thread at that part, which gives to the screw an unsymmetricalappearance, prevents the portion of the thread over the cone fromfollowing the lower portion with exactness, and diminishes. the holdingpower.

The object of myinvention is to obviate the making cuts of increasedwidth and diminished depth while going over the cone, in comparison withthe width and depth of the cuts along the cylindrical portionof the bodyof the screw, the increase of width and diminution of depth at any oneplace ha'vin g such reference to each other that the thread iseverywhere brought to an, edge without any difference in the inclinationof thesides, while the full outer periphery of the screw is everywheremaintained. This I have accomplished by introducing in an ordinarymachine for making wood-screws a. contrivance which causes the chaser toincrease. the width of its cuts over the cone proportionately as thedepth is less than what it is over the main part of the screw.

I proceed to describe the machine embodying my invention. v

In the drawings, Figure 1 is a plan of said machine. Fig. 2 is a frontelevation of the Fig. 3 is a rear elevation. Figs. 4 and lines inFig. 1. Fig. 6 is a cam in detail.

A is the frame of said machine. B is the spindle 5 to it the power isapplied, and for the most part it is hollow, carrying within it anordinary apparatus for holding the screw- This apparatusconsists of apair of jaws, a, which are opened and closed by a rod (not shown)connected with them, and extending back through the spindle, and havinga reciprocating motion derived from thesleeve 0 on the spindle, thesleeve and rod being connected. by a pin working in aslot, (notshown,)and the sleeve having a groove, 0, by means of which it obtainsalongitudinal reciprocating motion at proper times, by deviceshereinafter described.

Dis the tool-post, being an upward rigid 2 i "mess projection from arock-shaft, D, which has hearings at A A in the frame. The chaser. d isheld in a slot at the side of the tool-post by as hereinafter shown. Therock-shaft D has a longitudinal movement in its bearings equal in lengthto that part of the blank to bethreaded, and the spring just referred toalso acts to keep the shaft in contact, end to end, with a revolvingshaft, E, which has also a reciprocating longitudinal motion, derivedfrom a worm carried upon it, as shown, and operated by acorrespondinghalf-nut or female screw on a rocking lever, F, which ishinged to a shaft, F which has one bearing in a projection from andunder the main frame, and the other bearing in a sleeve, E fixed in themain frame, as shown. Through the outer end of the sleeve E and acrossthe end of the shaft F plays a wedge, c, forcing the shaft F at certaintimes inward longitudinally, and carrying with it the rocking lever, F,by means of a collar on the shaft coming against the hinge ofthelever,as shown. A coiled spring on the other end of the shaft F having one endin the main frame, keeps the rocking lever F up against the collaraforesaid, and forces the shaft back longitudinally as the wedge iswithdrawn, and this spring is so connected with the rocking lever as totend tokeep the worm of the latter out of gear with the worm of theshaft E. The shaft E not only revolves, but has a longitudinal movement.Near the end, in contact with the tool-post shaftD, as aforesaid, it hasa bearing in the main frame at A The other bearing is in a recess in theend of a revolving shaft, G, which has its bearing within the mainframe, principally in a cone-shaped projection, A, the shaft E beingfeathered to the shaft G.

The shaft G, at the outer end, carries a gear, g, into which a cog o 1the spindle B takes, as shown. screw-blank. It has a slot (see Fig. 5)across the edge, to embrace, that -'part of the screw-blank whichextends in front of the jaws a, and with the jaws holds the blank firmagainst the action of the chaser, the blank revolving in the slot on itsown axis.

The rest H is movable, and is so arranged in the machine as to-hebrought up to the blank at the moment the jaws a close to grasp thesame. This is accomplished by a slide-rod, h, having a longitudinalmovement across and under the front edge of a plate, I, the rod beingsupported by cross-pieces of the main frame, as shown. A projection, h,strikes the rest H, and forces it up to the blank. A slot in the rod hembraces the rear end of a fork, j, working in the slot 0 of the sleeve(J. This fork is a rigid projection from a sleeve, J, sliding on a rod,K, attached to a cross-piece of H is a rest or support for the.

the frame, as shown. The movement of the sleeve J is itself controlledby a cam which is on the shaft M, and revolves between 'two .pins, jj,in sleeve J. i

M is a shaft geared to the shaft G, and extending across the machinefrom end to end at tl1e.rear.- It carries most of the cams of themachine. 0 is a cam with two lifts, rigidly attached to a sleeve, 0, onthe shaft M, to operate the worm-lever F. Between the cams L and O is aclutch, N, keyed to the shaft M, and operating the cam L or the cam 0,according to its longitudinal position, and this position is determinedby means ofa slot, at, extending across the clutch, as shown, in whichplay two pins, 191?, being on the end of the fork P, which looselyembraces the clutch, and which has a pivot in the main frame, on whichit swings to the right or left. The fork P has also a projecting arm,the lower end of which follows a cam-slotted wheel, Q, on a shaft, R,having bearings under theframe, as shown. -At the other end of the shaftR is a star, B, one point of which is, struck by an arm, m rigidlyconnected to the shaft M,: at each revolution of shaft M. A spring, I,acting against a slot across the rim of cam L, assists in keeping thatcam steady when not in gear with the clutch N.

The plate S, before referred to, slides' in ways in projections A A ofthe frame, and, is rigidly secured to a movable yoke, T, which isslotted, as shown in Fig. 5, to permit the sliderod h and other parts ofthe machine to have motions underneath the plate I, in directions atright angles to the motions of the yoke. The movement of the yoke T inone direction brings the sliding plate S nearer to the blank, the chaserb consequently making a deeper cut, and this movement is accomplished bya slide-rod, V, working longitudinally in the main frame, and having atone end a projection, v, slightly wedged-shape, to forceuthe. yoke Tback as the wedge advances through the slot of the yoke. When the yoke Tis released from the wedge '27 of the slide-rod V, the spring, beforereferred to, on the projection (1 of the tool-post shaft carries backthe tool-post, the chaser, the plate S, and former s, and with themdraws over the yoke '1. At l the other end of the slide-rod V is aprojection, a, and a set of teeth, '0 one of which is shown in Fig. 3,against which projection and teeth act two peculiarly-shaped arms, W andW, revolving with shaft M, to which they are rigidly connected.

wedge 0 does not act upon the yoke T while the jaws a. are dropping thescrew and receiving blank. To bring the wedge 12 into play with the yokeT after the blank has been grasped, projections on arms W and Wsuecessively strike the projection 12 on the rod V, and move, the rodforward. After all the teeth have. been brought into' play, the rod VThe machine is so timed that the slide-rod V is drawn back, so that thewmss a is drawn back by means of an arm, v projecting from the rod, thearm 12 being struck by the upper arm of a'bell-crank lever, U,

' which is attached to the main frame and opmovement under the plate Iat right angles to the motions of the yoke T. This wedge has rigidlyconnected with it a pin, 2 which follows the cam Y, being forced intocontact with it at its depressions by two short arms, z 2 on a sleeverigidly attached to shaft M. The wedge 2 acts against the slide-rod V,and through that rod against the yoke T, drawing back the yoke wheneither lift of the cam Y (the two lifts being alike) acts upon the pin zthe slide-rod V, for this purpose, being free to move sidewise, andbeing separated from the wedge 2 by a gib, as shown in Figs. 1 and 5.The cam Y accordingly controls the movement of the plate S, and throughit the movement of the chaser toward the blank. While the pin 2 is inthe depressions of the cam Y it has no effect upon the tool-post andchaser, they, in fact, at that time being on the way back from the pointto the neck of the blank; but the lifts of the cam, at proper times,acting through the pin 2 and mechanism previously explained, hold thetool up to the blank to make a cut, and each lift of the cam is soshaped as to pull the tool, as it passes from neck to point, graduallyinward, to gradually increase the depth of the out till the full depthis reached, which is maintained for the remainder of the blank. This isindependently of the wedge 12, before referred to.

The operation of the cam Yis illustrated in Fig. 6, where the cam isshown as if removed from the side rim of a wheel, the curve of the wheelbeing disregarded. As the pin 2 passes from r to r the tool graduallyincreases the depth of its out. The pin reaching 4, from that point to rthe tool makes a cut of uniform depth.

While the cam Y has the above-described effect upon the bottom cuts ofthe tool, the cam M, before referred to, performs a similar duty withreference to the side cuts. This cam M is a cam of two lifts on shaft M,to operate the wedge 6, before referred to. This it does by means ofarocking lever, F which is pivoted to the main frame, as shown in Fig.4, and follows the cam by force of a spring coiled on the shaft on theend of which is formed the wedge 6. But the two lifts of the cam M, asshown in Fig. 4, are unequal, and the wedge e is, therefore, pushedfarther into or drawn back in the slot in the end of the sleeve E,before referred to, accordingly as the end of the rocking lever E is incontact with the greater or the lesser-lift; and it follows, from theeffect of the wedge 6 upon the shaft F and mechanism previouslydescribed, that when the rocking lever E is in I contact with thegreater lift of the cam M, one side of the chaser is brought into actionagainst the'blank, and when the rocking lever is in contact with thelesser lift the other side of the chaser is brought into action againstthe blank, the chaser thus alternately cutting on one side and theother.

The cam M is further divided, there being a decrease in radius from m tom of the greater lift, and an increase in the radius of thelesser liftfrom f to 6, while the remainders of both lifts are respectively ofuniform radius. Accordingly, when the rock-lever E is in contact withthe cam M at W, the chaser is cutting on the upper side of the thread,and presses with its greatest force or makes its greatest out toward thepoint; and this sidewise pressure gradually diminishes until the leverreaches m, when the sidewise pressure remains uniform for the rest ofthe cut. The next time the chaser goes over the blank at the beginningof the cut the rock-lever E is in contact with the cam M at f, and thechaser is cutting on the lower side of the thread, and presses, with itsgreatest force, toward the neck, and the sidewise pressure graduallydiminishes until the lever reaches 6, whence it remains uniform for therest of the cut. The cams Y and M are timed in combination, so that whenthe chaser is cutting to the least depth inward toward the axis of theblank it is making its greatest sidewise out toward the point or towardthe neck, as the case may be, and so that where the inward cut is ofuniform depth the sidewise cuts are neither increased nor diminished.

The chaser which I have used has a fetch or inclination toward the pointof the screw. This gives to the screw the strongest form of point whenthe entire screw is cut with a sin- 'gle tool; but this feature forms nopart of my invention, which has reference only to-cutting the threadover the cone and'cylindrical portion of the body of the screw, wherethe full outer periphery of the thread is maintained.

I claim-- In combination with an ordinary'screwthreading machine, themechanism described for accelerating, retarding, and limiting thesidewise cuts of the chaser over the cone and cylindrical body of thescrew proportionately to the depth of the cut of the chaser toward theaxis of the screw, so as to bring the-threads to an edge of a uniformangle over those parts without changing the outer periphery of thescrew.

GHARL ES D. ROGERS.

